Best tube choices for quad preamp???

ak47 · Aug 30, 2006

I have mesa tubes in my quad that are working ok but some are due for replacement pretty soon.

I am considering replacing all of them with GT 'mullard copies'. However, it occurs to me that using more specific choices for the different tube placements (V1, V2 etc..) will let me pinpoint the sound I am after and make them more accurately suited to each channel.

So what are people using? Any suggestions?

Timbre Wolf · Aug 30, 2006

You could peruse this thread - even though it is regarding the Triaxis, you can apply the principles.

For new-production 12AX7, I would recommend the Russian "Tung-Sol" 12AX7 as a low-microphonic tube with fine clarity, good low-end punch, and with airy high frequencies that are still a little rolled-off. I still use the NOS alternatives listed, though.

- Thom

Rock-On!! · Aug 31, 2006

I ordered some new 6l6 tubes from Doug’s Tubes for my lone star classic. While talking to him he also suggested trying a couple of new preamp tubes. I picked up one Tung-Sol 12ax7 and one Sovtek 12ax7LPS. I think he suggested the Tung-Sol in the V1 position, but I can’t remember where he suggested putting the Sovtek. Where would these tubes be most beneficial. I have some other various brands of 12ax7s that I might play around with in other locations, but I would like to use the new tubes where they would make the most improvement.
Thanks,

Timbre Wolf · Aug 31, 2006

Rock-On!! said:
I ordered some new 6l6 tubes from Doug’s Tubes for my lone star classic. While talking to him he also suggested trying a couple of new preamp tubes. I picked up one Tung-Sol 12ax7 and one Sovtek 12ax7LPS. I think he suggested the Tung-Sol in the V1 position, but I can’t remember where he suggested putting the Sovtek. Where would these tubes be most beneficial. I have some other various brands of 12ax7s that I might play around with in other locations, but I would like to use the new tubes where they would make the most improvement.
Thanks,

Do you have the tube task chart handy? Usually it is in the manual. Just off the top of my head, I'd guess the "Tung-Sol" would be V1 (closest to the 1/4" guitar input jack), and the LPS in V2 (next position, going towards the power tubes). The phase-inverter tube (closest to the power tubes) is also critical for determining your power tube breakup characteristics - you should carefully consider that position as well.

- T

Rock-On!! · Aug 31, 2006

Timbre Wolf,
Her is a layout of the tube chart.

I will dig through my other preamp tubes and see what else I have available. The amp is less than a year old so re-tubing was only necessary because of a cracked power tube. As long as I am doing this I might as well try to make it sound the best with what I have to work with.